The front-line refuse workers are not paid by the Spanish-owned company for time-off when ill – despite managers in the company being entitled to sick-pay from day one. About 20 staff are next set to go on strike on May 1 for 14 days over the issue.

Hull MP Emma Hardy is seeking a debate in Parliament calling for all future public sector contracts to guarantee company-paid sick pay for workers.

Ms Hardy told MPs during an appearance in the House of Commons on Thursday how the situation between FCC and its workers had left her feeling “angry”, especially given one of those striking is currently being treated for cancer.

Instead of sick pay, FCC’s Hull employees are incentivised not to take time off for illness with a £500 bonus paid to those with a 100 per cent attendance record at the end of the year.

The lack of a company scheme means the employees have to fall back on statutory sick pay (SSP) if they do get ill, with the Government paying out £92-a-week for up to 28 weeks to those eligible.

A spokeswoman for the local authority stood by the contract and said proper procedure was followed when the initial contract, which expires in 2022, was penned.

Alan Clark - in charge of waste for Hull City Council until the forthcoming election was called - joined the FCC workers' picket line to show support

“We expect when we sign a contract that the company is treating their staff in a lawful manner and is legally compliant,” said the spokeswoman.

The city council said it regarded the strikes as a matter between FCC Environment and its staff and urged "both sides to seek a resolution to the outstanding dispute".

That is despite Labour councillors and MPs joining the FCC workers on the picket line during their two strikes last month – including deputy leader Daren Hale, cabinet member for waste Alan Clark and Ms Hardy, MP for Hull West and Hessle.

Mr Hale, standing for re-election as a councillor in the St Andrew’s and Docklands ward on May 3, said FCC’s current sick pay policy was “not defensible”.

“I fully appreciate that we are bound into the contract until 2021-22,” said Mr Hale.

Daren Hale, Hull Labour's deputy leader (Image: Peter Harbour)

“But this is certainly something we will be looking at when the council contract comes back up. It seems to me that, in this day and age, sick pay should be a basic right.

“It would be a safety net for these people when they are very seriously ill. It [the current policy] is not defensible and that is why I support their rights to a sick pay scheme.”

Mr Hale said he would want FCC to become “consistent” with their policy and offer the company sick pay scheme to both front-line workers as well as those in senior ranks.

A spokeswoman for FCC Environment said the company was still considering its response to the fresh bout of strikes, along with Ms Hardy’s criticisms in the Commons.